Hume said that rational study of the world CANNOT discover or reason about morality. You cannot turn statements of the form "X is so" into statements of the form "X ought to be so". I've read a lot of post-Hume philosophy, but I've never seen a refutation of that point which convinced me.

... well, waht is the difference between the ancient science and the modern science? What is the role of human emotions in understanding myths? To whom and for whom is the Greek myths and why is it important to know mythology? =)

The standard view is that modern science differs from ancient science in the powerful weight given to experiment. The ancients did experiments every now and then, but not systematically, and they regarded mental reflection as a higher source of truth, being really philosophers rather than scientists. Modern science says "nullius in verba", take no one's word for it, and regards the only good theory as an empirically falsifiable theory.

Of course we now have string physics, which for practical reasons seems untestable, so many people snark that we've come full circle back to the ancient Greeks.

Should science be value-free?
SHould science isolate itself from value and morality?

if i understand you correctly, are you asking if science should have ethics involved? cloning for example is something we have proven scientifically we can do, yet is it ethical? morality is more of an individual base of values, such as abortion for example.

personally, i believe science should follow a code of ethics-a set of guidelines that entail a pursuit of how our world and life works with the intent of the overall good of humanity and life on this planet.

because the first post asks about the values of science, let's try to keep this topic on this course.

Hume said that rational study of the world CANNOT discover or reason about morality. You cannot turn statements of the form "X is so" into statements of the form "X ought to be so". I've read a lot of post-Hume philosophy, but I've never seen a refutation of that point which convinced me.

Well for the most part you were correct about Hume, although it is a little different than you suggest, but that particular example of "is/ought" is taken a little out of context. This is the is/ought dichotomy (yes I am sure someone will argue there is no dichotomy), Hume simply said that it does logically follow that whatever is so should be so, not that logic cannot answer of morality. Though never stated by Hume in such terms this is even similar to the problem of induction. Essentially, this is also G.E. Moore's Naturalistic-Fallacy that the moral good should not be confused with whatever is natural. This is not as simple as it may seem. As well, it is, of course, a moral decision to choose to utilize science and rational study to understand the world.
*Nico

Sure, Humean morality is kind of a forerunner to utilitarianism. Basically Hume's statement "is does not imply ought" says that we cannot determine the moral good from how things are presently; you could call these facts I suppose. It is not exactly that we cannot use logic in deriving value, although Hume felt feelings played a more central, but at the time many people attempted to assert that the ways things are is the way they should be. Basically, many people attempted to justify moral decisions by simply saying "Well, its just always been this way" and things of this nature and Hume went against and cautioned it. This really was not a central idea of Hume; it has only been made so by those who study him, like G.E. Moore. Some even try to argue that this is an argument against objective morality, but it is not. I hope I have clarified, I assume you are familiar with the problem of induction, which Hume did not coin but "discovered," that it does no real logical connection between what has been observed to be so and what is so.
*Nico

Yes I am familiar with the induction argument. Now what are your thoughts on objective morality and how it might be derived? I see the ESS arguments and the long sequences of playing prisoner's dilemma and so on, do you feel these are relevant?

I don't think that you can use empirical data to determine basic values, although you can use such to determine a right course of action based upon moral postulates.

I think that reason and knowledge can be used to discover value and arrive at a system of ethics based upon that. But this relies upon knowledge of the subjective (feelings), which cannot scientifically be measured.

My basic argument is that feelings have value. I cannot prove this to you, but I can state that we all individually know what pain and pleasure are, and we know the negative and positive (respectively) nature of these through experiencing them. These are the basic values. We can then apply logic and science to devise systems of optimizing these.